Pipelines are used for carrying a number of materials, particularly liquids, such as crude petroleum and gases. Often, these pipelines are very extensive, some times ranging over distances of hundreds of miles and long stretches of these pipelines are located a long way from habitations, rendering them not readily accessible if repairs should be needed. If there is a leak in the pipeline, this can usually only be discovered if there is a change of the delivery flow at the receiving end of the pipe, where a liquid is concerned or a drop in pressure at the receiving end of the pipe if a gas is concerned. By the time there is a noticeable change in these parameters, the leak may well have been in existence for a considerable time and, if the leak is relatively small, not until the next time the pipeline is due for a routine check. Thus, considerable amounts of fluid may have escaped with a possible deleterious effect on the local ecology.
One the presence of a leak has been determined, it is necessary to determine where the leak has occurred so that the necessary repairs to the pipeline can be made. In the meantime, the pipeline must be shut down to avoid further leakage. Discovering the location of the leakage, particularly where the pipeline extends for hundreds of miles, can be tedious and labour intensive as a complete inspection of the pipeline has to be undertaken up to the point at which the leak is found. This is made worse in the case that the pipe is carrying a gas since, unless the leak is large, such as a visible hole in the pipe, then there may be no visible signs of the leak and the pipe may need to be pressurised to enable the leak to be detected.
The present invention seeks to overcome some or all of these difficulties by providing an automatic leak detection system which can be made sufficiently sensitive as to detect even the smallest of leaks, will be able to pinpoint the pipe section in which the leak has occurred and can be made to shut off the section of the pipe in which the leak is present.